Spark-adjusting apparatus



w. EQSCHWARZMANN. SPARK ADJUSTING APPARATUS.

APPLICATION FILED DEC. 23, 1920.

Patented Oct. 24, 1,922.

JIIIW INVENTOR Wa/fgany 15 fic/zwarzma/m ATTORNEY Patented Oct. 24, 1922.

UNITED STATES PATENT OFFICE.

WOLFGANG E. SCHWARZMANN, OF LONGMEADOW, MASSACHUSETTS, ASSIGNOR TO AMERICAN BOSCH MAGNETO CORPORATION, OF SPRINGFIELD, MASSACHUSETTS,

A CORPORATION or NEW YORK.

SPARK-ADJUSTING APPARATUS.

Application filed December 23, 1920. Serial l Io. 432,707.

To all rv/(Mn. it vim/y concern:

Be it known that I, l/VOLFGANG E. SGHWARZMANN, a citizen of the United States, residing at Longnieadow, in the county of Hampton, State of Massachusetts, have invented certain new and useful Improvements in Spark-Adjusting Apparatus; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to a short-circuiting device for timing mechanism, such as is used in magneto ignition systems, and particularly magnetos having an interrupter housing carrying an end cap and a timing arm.

ln devices for short-circuiting the timing mechanisms of magnetos, it was usual heretofore to make special provisions for insulating the end cap from the interrupter housing and insulating the post, uponwhich was pivotally mountedv the spring clip that maintains the end cap in place upon the housing, from the magneto frame or casing, a resilient electrical conductor being usually electrically connected to the end, cap and the interrupter fastening screw within the housing, and for the housing to carry an external projection, which when the housing is rotated into fully retarded position, would. contact with the post and thus shunt the primary circuit from the interrupter through the end cap and. the post to ground by way of the housing, thus making an indirect way of grounding or short-circuiting the interrupter and requiring the insulating of the end cap from the housing and the post from its mounting on the magneto frame or casing.

It is, therefore. an object of my invention to construct a magneto with a primary cir-- cuit shunting device which omits the insulating means for the end cap as well as for the post upon which the spring clip is mounted. and also to enclose or house the short-circuiting device within the interrupter housing so that the relatively movable rupter an an interrupter housing compris ing a movable cam ring and an end cap, has means, such as an anchoring member, preferably in the form of a forked member, for holding the end cap stationary, such means being preferably connected to the end cap and a post located on the magneto adjacent the camp ring, as by fastening the anchoring member to the end cap and in engagement with the post or by fastening an end of the premature short-circuiting by contact therewith by outside objects.

In the accompanying drawing, illustrating preferred and modified embodiments of the invention:

' Fig. '1 is an end view of a magneto with a short circuiting device mounted in position upon. the mechanical. interrupter thereof; Fig. 2 is a part side view and a part sectional. view taken on line 2-2 of Fig. 1; Fig. 3 is a transverse sectional view taken on line 3-3 of Fig. 2; Figs. 4 and 5 are views similar to Figs. 2 and 1, respectively, showing another embodiment of the invention; Fig. 6 is a view similar to Figs. 2 and 4 showing a still further embodiment of the invention; Fig. 7 is a sectional vew of the end cap used in the embodiment shown in Fig. 6; Figs. 8 and 9 are views similar to Figs. 6 and 7, respectively, showing a still further embodis ment'of the invention.

Referring more particularly to the drawing, a magneto 1 has an interrupter housing 2 at an end thereof, a timing lever 3 being connected to a cam ring 4 rotatably support ed upon the housing in a well known manner. Within the interrupter housing may be included the usual interrupter elements comprising an interrupter fastening screw 5 with which engages a contact brush 6 carried by a resilient conducting strip 7 mounted upon an end cap 8 held in bearing 01;-

lIG strip thrust contact with the end of the cam ring by a spring 9 pivotally niounted upon the end of a post 10 located on the magneto ad acent the cam ring at. The strip 7 is fastened to the end cap 9 by a screw 11 which is screwed into an insert molded into the base 152 of insulating material on the cap 9, an insulating strip or washer 13 being interposed between the end of the strip 7 and the inner surface of the cap 1 '9 in order that current trom the interrupter to l will not be shortcircuited throiruh the cap "3 as will more clearlyappear hereinafter. The outer end of the inbe tl'ireaded to receive a binding nut :l l. lletween the end of the strip 7 and the head of the screw 11 is connected an angular contact l'UGlllbQl' 15 with one of its legs 16 extending parallel to the axis of the interrupter and cam ring and curved or arc-sl'iaped to enable its ready engagement with a screw contact 17 fastened to the cam ring 4t, the screw being grounded through the c: sing or? the magneto through the cam ring); l and the housitngQ.

In the form or embodiment illustrated in Figs. 1, 2 and 3, the spring 9 has a projection 18 at its inner end pressing; into a depression 19 for holding the end cap 9 against the end of the cam ring 4:, the other end of the spring; 8 being pivotal ly secured to the end of the post 10,so that the spring when grasped by a clip 20 and turned about the axis of the post 10 for disengagement and engagement oil the spring; 9 with the end cap. 1

D For the purpose ol maintaining the end cap 8 and the parts, such as the contact brush 6. spring; 7 and contact member 16. in stationary position during the retarding; nuwement oi the cam ring 4- and the contact screw 1'7, the cap Fl has l astened thereto, by 111621115 oil rivets 21, an end. of an anchor member 252, he other end of this member being tor-lived or having prongs 23 spanning the post 10 so that any tendency to rotate the end cap. 8, due to its frictional engagement with the angnlarly moving cam ring, "will be prevented since angular movement 01 theanchor member about the axis of the interrupter and cam ring is prevented by reason oi the contact of the prongs on both sides of the post. In this way the end cap and the contact part .16 are held staticinar 1 and the contact screw 17 is moved into or out of contact with the part 1.6 as the cam ring 4 carrying such screw 17, is 'angu'larly moved respectively, to or from fully retarded position. Upon the engagement of the contact parts-1.6 and 17, the primary circuit normally passing through the interrupter elements is short-icircuited or shunted to ground through the end fastening screw 5, contact brush 6, spring-strip 7, angle member 15. contact lop; 16, (contact screw .17 and cam ringsto the housing 2 am} hence to ground. In Fig. 3 .is illustrated, in full lines, the position of the timing lever 3 during the normal operation of the magneto, at which time the contact screw 17 is separated from the contact part 16, and in dotted lines is shown the position occupied by the timing lever 3 and contact screw 17 when the lever and cam ring a are rotated to fully retarded position at which time the contact screw 17 is in contact with the contact part 16 and the interrupter primary circuit is shunted to ground. I

In the embodiment illustratei'l in l igs. 4t and 5, the end cap 8 is held from rotation by means of a pair of rivet pins 24 rigidly fastened to the cap 8 and located one on each side c1 and in contact with the side e lges of the spring 9, so that any tendency to rotate the cap 8 during the angular movement of the cam ring is prevented since angular movement of the pins 2 .1., about the axis of the cam ring 4, cannot occur due to the contact of the pins 2 1 at both edges of the spring 9.

In the "term of device shown in Figs. 6 and '7, the end cap 8 has a radially extending depression or trough 25 having side shoulders 26 and within which the spring; 9 is adapted to be seated with its side edges in 1 contact with the shoulders 26, so that tend ency to rotation of the cap 8' is prevented by the engagement of the shoulders 26 with the lateraledges of the spring 19.

in the structulie shown in Figs. 8 and 9, the end cap 8 is made of insulating material, such, as a condensation product, as bakelite and :has a substantially fiat radial recess 2" having lateral shoulders 28 and within which the spring 9 is adapted to rest with the side edges of the spring engaged by the shoulders 23. so that tendency to rotation by the cap 8" is prevented by the contact oi the shoulders 28 with both sides of thespring- 9. The cap 8 also has a boss 12*" in which embedded, when the cap is mold ed. an insert 2-9 having an annular groove 30 for maintaining it in place in the insulatin-g material. and being suitably threaded to receive the threaded portion of the screw 11 tor securing' the contact member 15 and the spring strip .7 in place. it will be olw served here that inasmuch the cap 8 of insulating materialthe insulating washer 13 of the forms ofdevices shown in Figs. 1 to Tinclusive, is omitted. It will also vbe notedLt-hat, inasmuch as no leadneedhe connected to the usi-ial binding post or nut 11.. the latter can be omitted as shown in Figs. 8 and 9,.such binding member 141- being shown in Figs. 1 to 7 inclusive, merely to indicate thatthe invention is applicable to or adapted for use with presentrend caps.

The primary circuit of the magneto passes through the cam shaft, which carries the "tasteningscrew 5, to the contact carrying elements of the interrupter mechanism in the usual manner, but at certain times of op eration it may be desirable for the primary circuit, of the interrupter to be short-circuited or grounded so that no induced current may be effected in the secondary circuit of the ignition system, particularly in the event of driving an automobile down hill when it is desired to use the engine as a brake, either with or without the mechanical brakes usually provided on the vehicle. In such case, as in others. it is usual to retard the ignition to the full extend and to provide some means of short-circuiting or grounding the primary circuit at the fully retarded position oi? the ignition device. Heretofore, the grounding or short-circuiting shunt passed from the fastening screw through a conducting piece electrically connected to the end cap of the interrupter housing, and thence through an end cap spring and the post sup porting the spring. It is necessary in such cases to insulate both the cap from the housing and the post from the magneto casing and for the interrupter housing to carry a contact which, when the housing is rotated to fully retard position, would engage with the post for completing the grounding shunt by way of the interrupter housing. It will be apparent from the above description and illustration upon the accompanying drawing, that l have eliminated the necessity of insulating the end cap and the post from the interrupter housing and the magneto casing, respectively. and by otherwise simplifying the structure in many respects.

Having thus disclosed my invention What I claim is:

l. magneto having a mechanical interrupter and an interrupter housing comprising a mo "able cam ring and an end cap, means for holding said cap stationary, an insulated. contact carried by said cap and electrically connected to said interrupter,

J and a grounded contact carried by said cam ring and engageable with said insulated contact at the fully retarded timing position of said cam ring for short-circuiting said magneto.

2. A magneto having a mechanical interrupter and an interrupter housing compris ing a movable cam ring and an end cap, and

a post on said magneto located adjacent said cam ring, means connected to said post and said cap for holding said cap stationary, an insulated contact carried by said cap and electrically connected to said interrupter, and a grounded contact carried by said cam ring and engageable with said insulated contact at the fully retarded timing position of said cam ring for short-circuiting said magneto.

3. A magneto having a Inechanical interrupter and an interrupter housing comprising a movable cam ring and an end cap, and a post on said magneto located adjacent said cam ring, an anchoring member fastened to said cap and engaging said post for holding said cap stationary, an insulated contact carried by said cap and electrically connected to said interrupter, and a grounded contact carried by said cam ring and engageable with said insulated contact at the fully retarded timing position of said cam ring for shortcircuiting said magneto.

4. A magneto having a mechanical interrupter and an interrupter housing comprising a movable cam ring and an end cap, and a post on said magneto located adjacent said cam ring, a forked member fastened at one end to said cap and the other end thereof spanning said post for holding said cap stationary, an insulated contact carried by said cap and electrically connected to said interrupter, and a grounded contact carried by said cam ring and engageable with said insulated contact at the fully retarded timing position of'said cam ring for short-circuiting said magneto.

A magneto having a mechanical interrupter and an interrupter housing comprising a movable cam ring and an end cap,

means for holding said cap stationary, an insulated contact carried by said cap and electrically connected to said interrupter, and a grounded contact carried by said cam ring and engageable with said insulated contact at the fully retarded timing position of said cam ring for short-circulting said magneto.

In testimony whereof I afiix my signature.

WOLFGANG E. SCHWARZMANN. 

